yeah keep clicking the tiles until they fall down, then put the hose down the hole. if u have made the torch work then u can go down there and find the key u dropped through the grating! hope that helps!
Ah yes, that QUEST computer - took me ages, iirc, yet the answer was so easy in retrospect.....
BUT at this point in time, lol, I can't recall - it was many months ago
EDIT - just looked back at the original thread, and when the QUEST computer loaded, I had an error on the page - this was why I couldn't do it - TRY a refresh and see if it becomes obvious.